The Issaquah Alps is the unofficial name for the

highland Highlands or uplands are areas of high elevation such as a mountainous region, elevated mountainous plateau or high hills. Generally speaking, upland (or uplands) refers to ranges of hills, typically from up to while highland (or highlands) is ...

s near

Issaquah, Washington Issaquah ( ) is a city in King County, Washington, United States. The population was 40,051 at the 2020 census. Located in a valley and bisected by Interstate 90, the city is bordered by the Sammamish Plateau to the north and the " Issaquah ...

, a suburb of

Seattle Seattle ( ) is a port, seaport city on the West Coast of the United States. It is the county seat, seat of King County, Washington, King County, Washington (state), Washington. With a 2020 population of 737,015, it is the largest city in bo ...

, including Cougar Mountain, Squak Mountain, Tiger Mountain, Taylor Mountain, Rattlesnake Ridge, Rattlesnake Mountain, and Grand Ridge. The term was invented in 1977 by noted nature author Harvey Manning within the pages of his trail guidebook ''Footsore 1'', elevating their status from foothills to "Alps" to advocate preservation. Manning himself lived on a developed section of Cougar Mountain in his "200 meter hut". In 1979, Harvey Manning helped to found the Issaquah Alps Trails Club to care for the trails and to push for public ownership of the Alps. The IATC, which is headquartered in Issaquah (nicknamed "Trailhead City"), conducts frequent guided hikes throughout the Alps. The Issaquah Alps follow

Interstate 90 Interstate 90 (I-90) is an east–west transcontinental freeway and the longest Interstate Highway in the United States at . It begins in Seattle, Washington, and travels through the Pacific Northwest, Mountain West, Great Plains, Midwest, a ...

from the shore of

Lake Washington Lake Washington is a large freshwater lake adjacent to the city of Seattle. It is the largest lake in King County and the second largest natural lake in the state of Washington, after Lake Chelan. It borders the cities of Seattle on the west ...

almost to the western face of the Cascade Range. The hills are composed of

andesitic Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained ( aphanitic) to porphyritic in texture, and is composed predomi ...

volcanic rock lying on top of older tightly folded rocks from the coastal plain of the North Cascade subcontinent that docked with Washington about 50 million years ago as the entire continent of North America moved west across the ocean. The Alps were heavily eroded by

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such a ...

s in the last

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gre ...

. The Vashon lobe of the ice sculpted Rattlesnake Ledge, steeply carved the east and west sides of Squak Mountain, and deposited a large erratic on Cougar Mountain,

Fantastic Erratic Glacial erratic boulders of King County are large glacial erratic boulders of rock which were moved into King County, Washington by glacial action during previous ice ages. The Pleistocene ice age glaciation of Puget Sound created many of the ...

. Cedar Butte rises abruptly from the

moraine A moraine is any accumulation of unconsolidated debris ( regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sh ...

between Rattlesnake Ledge and the absolute front of the Cascades. It is sometimes considered part of the Issaquah Alps but it is a relatively young symmetrical volcanic cone and is therefore more closely related to neighboring Mount Washington to the east than the old weathered hills of the majority of the Alps.

Summits

* Cougar Mountain,

elevation The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § ...

* Squak Mountain, elevation * Taylor Mountain, elevation * Tiger Mountain ** Middle Tiger Mountain, elevation ** East Tiger Mountain, elevation ** South Tiger Mountain, elevation ** West Tiger #1, elevation ** West Tiger #2, elevation ** West Tiger #3, elevation Rattlesnake Ledge, seen from Rattlesnake Lake

Rattlesnake Ledge, seen from Rattlesnake Lake

* Rattlesnake Ridge ** Rattlesnake Ledge, elevation ** Rattlesnake Mountain (East Peak), elevation ** Rattlesnake Mountain (West Peak), elevation

References

* *

External links

Issaquah Alps Trails Club
*Trail reviews of hikes in the Issaquah Alps a
Hiking with my Brother
{{DEFAULTSORT:Issaquah Alps Cascade Range Mountain ranges of Washington (state) Landforms of King County, Washington